No thanks. One reason I moved away from DSLR's was the increasing bulk and weight of the system which includes lenses. No way would I take the behemoth existing lenses, add an additional adapter for more weight and bulk and then stick that only a mirrorless body...just to get a lens that has not been designed for that mirrorless system...but rather tacked on. Not a chance.
I want the benefits that go along with mirrorless and that is a reduction of bulk and weight...not a Frankenstein conglomerate of modern camera with lenses designed for a prehistoric system.
You act as if "you" are the measure of all things ... and that all companies should alter their agenda to build 'you' the perfect gear for 'your' needs, to the exclusion of all others
Here's a thought you haven't been able to consider, thinking only of your own need:
other people
love those "behemoth lenses" without which they couldn't capture the wildlife/action that makes
their world go round-and-round.
Now, if the finest telephotos can be have their dimensions reduced in the future, without losing quality, hey, we'd all welcome that. But right now, "it is what it is." Sony simply has nothing to offer professional sports/wildlife photographers ... except to (how did you say it?) offer a "Frankenstein conglomerate" of other companies' adapters + other companies' lenses. Yet even that is a loser for Sony.
In fact, in DP Reviews latest article, put up yesterday, concludes the recent "true pro" effort from Sony, the A9, proves dismal with Canon's two best lenses. The article directly criticizes the smallness of the A9 compared to true pro cameras (1Dx/D5):
"Battery grip all-but-required for comfortable use with larger lenses."
"...
it seems like using off-brand glass while you wait for Sony to catch up just isn't a great option ... the lack of true subject tracking (Lock-on AF modes) or continuous focus at speeds higher than ~2.5 fps (or in video) will probably be a deal breaker for many fast-action photographers ... like all previous Sony bodies, you'll only have access to the a9's slowest continuous drive mode (2fps) when you're adapting your own glass."
Don't believe me, read the article:
Sony a9 falls short with Canon 300mm and 400mm lenses.
If you can't handle larger glass, that's okay ... enjoy your gear. However, your repeated angry outbursts against large, elite telephoto lenses is getting old.
Allow people to make their own choices.
Thanks.